Roller Wear

Hi,
Can anybody tell me what the wear limits are for inking rollers in an SM52. I'm sure there is a lower limit beyond which the adjustments cannot be reached? What is this limit for each roller or is there a rule of thumb? Eg: my RED form roller should have a diameter of 54mm but in actual fact (measured using a vernier calliper) is 53mm, i.e. 1 mm less. Will this impact the roller pressure adjustments to the point that print quality is impacted? Once a roller has worn down can it be switched into another position?

 

At 1mm reduction of diameter, you get to the point where positive contact at either plate or oscillator is possible, but not at both.

 

Dear Peter,
As Junker mentioned, for me you can print until the reduction is max.2mm if there is not a visible were in the rollers.

 

I am curious why not both? Doesnt the adjustment screws compensate for reduction -except for ductor which can be a tough cookie for HD-

 

The answer to that has something to do with geometry. Or algebra. Or trigonometry. I was too busy checking out the girls in my math classes to give a concise answer to that . Hey, to try to answer that, the decrease in diameter past a certain point, when adjusting, or "rolling" the roller into position, will require you to go so far in one direction, that the other adjustment doesn't have enough travel, or "cam action" to go the other direction. Best I can do. This is not something I read in a service manual or was told or taught, it's just something that has bit me in the arse a few times in my career. Like, after going in on a service call, where customer couldn't get proper adjustment, and after fighting the problem for an hour finally led me to pull roller to see what I was missing...

 

I'm surprised that Heidelberg don't give an exact figure for roller wear. I don't have access to HD service manuals or the famous Sherlock BUT as an engineer (ex KODAK for 12 years) I've replaced many rollers in many types of machines and there normally was a specified wear limit to stop you wasting too much time chasing unobtainable adjustments values. Does anybody here have OFFICIAL Heidelberg data on this ? Also my experience was that once a roller had worked to its limit, other related bits and pieces (bearings, limit screws / blocks / cams and springs) would be worn/dirty/lacking lubrication etc and this tended to aggravate the problem and that fitting a new roller under these conditions meant that the new roller would have a shorter life anyway.

 

I’ve never seen any documentation such as that, Peter.